Four distinct positive integers—A, B, C, and D—add up to 20. A is twice as large as B. C is 1 greater than D. D is greater than A. What are the values of A, B, C, and D?
A = 2, B = 1, C = 9, D = 8
If B = 1, then A = 2. Since A + B + C + D = 20, 2 + 1 + (D + 1) + D = 20, which simplifies to 2D + 4 = 20, so 2D = 16 and D = 8. Then C = 8 + 1 = 9. Checking conditions: 2, 1, 9, 8 are distinct positive integers, 8 > 2, and 2 + 1 + 9 + 8 = 20.
About this riddle
Logic riddles give you a few facts and ask what must be true. List what you know, cross out what cannot be, and see what is left.
Difficulty: Medium. More like this: Logic riddles with answers or try Einstein's Logic Grid for a different kind of puzzle.
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